Metal roofs are commonly used, especially in commercial and industrial buildings. In existing metal roofing systems, typically a closure piece is attached to the upper end of the roofing panel to seal the space between the upper end of the roofing panel and the ridge cap. The closure piece typically conforms to the profile of the roofing panel. The profile of the roof panel controls the height and width of the closure.
Historically, if a ridge vent was incorporated in the roofing system, the vent was separate from the closure and sat on top of the closure between the closure and the ridge cap.